It is known that internal combustion engines are provided with a cylinder head, which sits above the cylinders on top of the cylinder block. It closes in the top of the cylinder, forming the combustion chamber. Cylinder head are often realized in aluminum or other light metal alloys. In most engines, the cylinder head also provides space for the passages that feed air and fuel to the cylinder, and that allow the exhaust to escape. The cylinder head is also a place to mount the valves, spark plugs, and fuel injectors.
In particular, to mount valves and related valve springs, ensuring the closing of the valves, cylinder heads are also provided with bosses. According to a known design, bosses are part of the cylinder head casting and have a circular shape. The boss includes a central opening to allow the assembly of the valve. The boss also comprises an annular seat, around the central opening, for the assembly of a valve spring and a valve sealing element. Said valve spring is a compression spring, whose elastic force guarantees the closing of the valve, when the latter is not pushed by the cam of the camshaft in its opening phase. The valve spring transmits its elastic force, through the valve sealing element, to the boss seat, which accommodates the valve sealing element.
An investigation about the present cylinder head design, and in particular about the valve spring boss could be useful since engine manufacturers are generally struggling to obtain weight reductions wherever possible.
Therefore a need exists for a new design, defining a cylinder head lighter without any disadvantages for the function.